It is difficult to spread that circlip in the CV joint.
Once I had an experience where I could not get the CV joint off of the
wheel end of a driveshaft no matter how well I spread the circlip nor how
hard I tapped on the CV joint.
The joint itself was not needing replacement, so I eventually removed the
CV joint off of the other end of the shaft and worked the new boot on from
the opposite end.
After that new boot and fresh grease, it has given me no problems since.
Enjoy,
Eric Kissell